Faculty Profile

Professor Studies Impact of Chemical Exposures on Child Brain Development

Birgit Claus Henn, associate professor of environmental health and director of the PhD program in environmental health, is working to understand the harmful effects of joint exposure to multiple chemicals.

Birgit Claus Henn first developed a curiosity about environmental exposures and children’s health well before she understood the subject as a core area of public health.

As early as second grade, she aspired to be a pediatrician. Then, two middle-school science fair projects—one on the effects of pollutants on brine shrimp (sea-monkeys) and another that examined levels of UV protection in lenses—sealed the deal.

Now, as an associate professor of environmental health and the director of the PhD program in environmental health at the School of Public Health, Claus Henn has built a solid portfolio of research that explores the issues she first inquired about as a child.

An environmental epidemiologist who joined SPH in 2015, Claus Henn’s research spans several disciplines, and her primary interests revolve around gaining a deeper understanding of how mixtures of environmental toxicants affect fetal and child development. To date, there is minimal research on the harmful effects of joint exposure to multiple chemicals, and Claus Henn’s work focuses in particular on the impact of these toxicant mixtures on child brain development.

“There is an infinite number of possible combinations of chemical exposures, so one aspect I’m focusing on understanding is whether there are certain combinations of chemical exposures that occur more often,” says Claus Henn. “I’m looking to see whether there are some common combinations of chemicals that we should focus our research on in order to have the greatest impact, whether these combinations occur more in certain subpopulations, and what their joint effects may be.”

One of her favorite projects involves a cohort of children, who are now adolescents, in a region of Italy where there is a lot of ferroalloy industry, and thus, concern about exposure to metals in the community.

“We’ve been working to understand how the mixture of metals might impact children’s cognitive function, other behaviors, and also their motor function,” she says.

Claus Henn is also collaborating with the Department of Epidemiology on a project examining exposure to endocrine-disrupting chemicals and the health of reproductive-aged Black women.

“Even though levels of these endocrine-disrupting chemicals tend to be higher in reproductive-aged women and non-Hispanic Blacks, there is little research on how these exposures contribute to the racial disparities in certain health outcomes, such as uterine fibroids, which is the focus of the project,” she says.

In addition to studying exposures to multiple toxicants, Claus Henn is also expanding her research focus to explore the impact of multiple chemicals in combination with non-chemical environmental factors.

“We need to understand, for example, how this mix of chemicals is also interacting with non-chemical factors, such as stress or dietary factors or household characteristics, to impact our health and the health of our children,” she says. A new project that she has begun takes a look at the interplay between toxic metals and essential nutrients in relation to acute myocardial infarction in a population-based prospective cohort in Denmark.

The PhD program that Claus Henn directs at SPH is one of the few programs of its kind in the nation that specialize in investigating exposure-related health outcomes in community settings.

“Doctoral students are such an integral part of the fabric of our department,” she says. “This is a unique and distinguishing characteristic of our program. I was struck by this when I joined BUSPH, and we have maintained and even elevated this over the years.”

PhD students also are regularly invited to provide input on department decisions and participate in several department committees, she says. “As faculty, we highly value their innovative ideas and suggestions, and we take PhD student mentoring to heart.”

The inter- and multidisciplinary nature of environmental health means that Claus Henn is constantly learning, too, as she continues to examine problems from multiple angles.

“What I love most about my work is being able to think about a real-world problem that I might actually be thinking about in relation to my own kids, and then assemble an interdisciplinary and multidisciplinary team to start addressing it,” she says. “While there is utility for many chemicals in our world, we do owe ourselves an understanding of how they might be hazardous especially for the developing little humans we want to protect.”